Incorporating whole grains in granola bars?

I've been dabbling with granola bars recently, and so far I'm pretty happy with the results - I've been using a basic recipe for a "playdate bar" which is non-corn syrup, mix the dry, add the wet, bake it up, standard version.

So does anyone know the optimal way to use whole grains? EG would you cook barley, toast it, then use it? That seems like it would be mushy. Just toast a grain? - seems like, as with the millet, it would be too hard and raw for the ~30 min baking time of the bars.

Commercial bars seem to use puffed grains - is that the way to go? In which case do I need to buy puffed grains, or is there a way to do this at home?

Thanks for any thoughts. I want to make something that will really fill up my kids, with good whole grains, but not be as chemical and sugar laden as commercial brands. I also enjoy making it myself even if there are some pretty good commercial ones out there, like Kashi . . .

Not a whole grain, but if you're looking to fill up your kids I find a nut meal does the trick. I grind them up in my food processor and store in the freezer or buy almond meal from Trader Joe's and add to my oats, whole wheat pastry four, wheat germ, etc.

I don't try to imitate the commercial ones but use oats, wheat germ , sometimes bits of leftover cooked grains ( i like wheatberries for the chewiness) and sometimes commercial brown rice krispies. And chopped nuts .

I thought I remembered reading about puffed quinoa in granola, so I tried googling, but I can't actually find instructions for puffing it (except that you do it the way you would rice). It seems like it's sold already puffed though...http://www.coronilla.com/en/products/...

I'm actually making granola bars right now and I just used oats for grains, but I dumped flax and chia seeds in, hoping that they will both help them hold together and add some omega-3's.